Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Conventionally, microprocessors are designed to operate at low voltages, typically about 1.2 volts (V), and future microprocessor operating voltages could be as low as 0.2 V, while their operating currents could be quite high, for example more than 100 amps (A). A known on-going trend aims for a general voltage reduction in most types of digital and analog electronic circuits. Memory circuits, communication circuits, analog-to-digital converters, and other applications are migrating to lower voltages.
A conventional parallel core interconnection of a four core microprocessor 100 is illustrated in FIG. 1. As shown, the four microprocessor cores 102 are connected to one another in parallel and to a voltage regulator module (“VRM”) 104 supplying a low-voltage high-current power. Typically, high currents may require extensive wire connections, with dozens or even hundred of pins (not shown) dedicated to power supply and grounding. Moreover, voltage and current regulation can be made difficult by the connection lengths and extreme current slews. In many cases, there are further function blocks within an individual core, such as memory, arithmetic processing units (APUs), input-output interfaces (I/O), and others. An operating performance of these function blocks is typically optimum when they can operate at different voltage levels.
In general, the power consumed by processors and other digital circuits is proportional to the square of their input voltages, which may give incentive to seek a decrease of operating voltages. However, it is problematic to provide a tightly regulated power supply at low voltages and high currents in an efficient manner. In fact, there are fundamental limits to power conversion at these low voltages. For example, power converter losses are inversely proportional to the square of the power supply output voltage, which may offset the power consumption advantages in the power-supplied processor or digital circuits.
VRMs and other power supplies use relatively large transistors and other switching devices to keep their power losses low. These power supply designs can introduce a problem of dynamic performance because the power electronics needed to implement a power supply are inherently slow compared to the electronics used in modern digital circuits. Moreover, conventional power supplies provide their own output regulation. They are expected to maintain a substantially fixed output voltage regardless of the imposed load power.
Therefore, it would be beneficial to provide a power supply system and method that overcome the above discussed performance limitations incurred while supplying power to modern electronic circuits.